Warren Buffett just provided a clear reminder that even at 86 he hasn't lost his touch. Berkshire Hathaway, the insurance-based conglomerate he runs, is buying up to 38 percent of Canada's Home Capital and extending it credit of C$2 billion, or about $1.5 billion. It's a rescue right out of the Omaha investor's 2008 playbook that promises to steady the troubled mortgage lender. The favorable terms illustrate how his imprimatur is as coveted as his cash.

The Canadian company made clear what really mattered. Independent director Alan Roy Hibben said Buffett was chosen over an eyebrow-raising group of 70 other potential suitors because the transaction provided an endorsement "from a world-renowned investor." Likewise, the first bullet point in the press release emphasizes fame over finance.

Home Capital can use all the help it can get. Allegations by Ontario regulators of misleading investors sparked a run by depositors and forced the firm to hastily arrange borrowing capacity on onerous terms. The short-term, high-interest savings accounts Home Capital relied upon for growth have dwindled to just over C$100 million from some C$2 billion in March. Its shares plunged nearly 80 percent.

Buffett's arrival sent the stock back up 10 percent, an uplift that comes at a cost. Berkshire is buying nearly a fifth of the company at a 36 percent discount to the last closing price. Home Capital is relying on a financial-hardship provision on the Toronto exchange to push the sale through without shareholder approval. And the Oracle of Omaha agreed to acquire more deeply discounted stock to roughly double his ownership stake if Home Capital's existing owners consent.

Assuming his whole investment package goes through, Buffett already has booked a gain, on paper at least, of 65 percent on his C$400 million investment. A juicy interest rate and standby fee on the line of credit would yield roughly another C$200 million a year if fully tapped.

Even with the new investor at its side, however, Home Capital faces an uphill climb. The Canadian economy is growing at less than 2 percent annually. Authorities have taken steps to cool off a housing boom and home sales fell 6.2 percent in May. The regulator's allegations have yet to be resolved. Buffett's seal of approval is valuable, but only extends so far.

Commentary by Tom Buerkle, associate editor at Breakingviews. Follow him on Twitter@tombuerkle.

For more insight from CNBC contributors, follow@CNBCopinionon Twitter.